Short answer is for an overnight--don't sweat it and carry what you think need and a bit extra. White gas is rather light. But if you'd like to figure out your minimum fuel use just for the heck of it (and for future trip planning) you have to become your own data source. Your specific gear and meals and techniques throw huge variables into the answer.

Fill and weigh your fuel bottle to the gram or tenth ounce. Using your stove, your pot and your windscreen, cook your planned meals--outdoors on a cool, breezy day--letting the stove completely cool between so you have to prime it each time.

Weigh your fuel bottle--the difference will be the amount of fuel you need. Now imagine doing the same in a nasty storm and add a bit more to accommodate the efficiency loss.

Cheers,